Re: Bug in grep when using both --after-context and --invert-match

[Bob Proulx]

Paul Jarc wrote:
> Oni Studio wrote:
> > Logically, i tried:
> > grep -v -A4 'zone "domain.com' /etc/bind/zones > /etc/bind/zones.new
> >
> > This did not produce the desired effect.
> 
> Right.  This gives you eery line that does not match your pattern,
> along with the following four lines.  Here's one way to get what you
> want (untested):
> grep -A4 'zone "domain.com' /etc/bind/zones |
> diff - /etc/bind/zones |
> sed '/^> /!d;s/^> //'

Here is another way that I think I simpler using sed.  Illustrated
using seq to generate test input.

  seq 1 9 | sed '/4/,+3d'
  1
  2
  3
  8
  9

So in your case something like this (untested):

  sed '/zone "domain.com/,+3d' /etc/bind/zones

The sed -i,--in-place option can be very useful in this context too.

Bob